Normally, people don’t associate Google with hardware. Besides search, Google’s mostly known for both software and providing innovative and useful services on the Net.

But the company recently unveiled two hardware products that are causing a stir. One of them, its second branded smartphone called the Nexus S, you can buy today. The other is a notebook computer you may never be able to buy, but if you’re the kind of person Google’s looking for, you may just get one for free.

This week, I’ll take a look at the notebook and next week, the Nexus S.

Cr-48 — Free (if you’re lucky). Earlier this month, Google began giving away a 12.1-inch notebook to people who wanted to test drive the Chrome OS, a PC operating system it’s been developing for almost 18 months. You can apply at http://services.google.com/fb/forms/cr48advanced/,

but hurry: The application deadline is 2 a.m. Wednesday.

If you’re the type of user Google’s seeking, you won’t get any notification. One day, without warning, you’ll receive a notebook with a black, rubbery finish that looks a lot like the black MacBook Apple sold from 2006-2008. But unlike a Mac ­— or a Windows machine, for that matter — it doesn’t run programs that live on its hard drive. In fact, it doesn’t even have a hard drive. All the applications and files live on the Internet, a scenario known as cloud computing.

The Cr-48 is a nice notebook with some rough edges. It’s got a 12.1-inch screen and a trackpad similar to current Apple notebooks, in that the entire pad is a button. You can also just tap to click.

The familiar PC keyboard has been overhauled on the Cr-48. The traditional top-row function keys are replaced by keys that mostly control hardware features, like brightness and volume. There are also keys for moving back and forth in the Chrome browser. There’s no caps-lock key; it’s replaced by a search key. Google says it left off the caps-lock to keep people from SHOUTING IN ONLINE FORUMS, but you can still hold down the shift key with your pinky if you insist on being annoying.

The notebook has a 1.6-GHz Intel Atom processor, 2 gigabytes of memory and uses a paltry 16 GB of flash memory for storage. You don’t need much storage when programs and the documents you create are in the cloud.

In fact, when you start using the Chrome OS, all you see is a browser — it’s identical to the excellent Chrome browser you can install on Windows, Mac and Linux systems. You can’t minimize it, and there’s no desktop. You can have as many tabbed pages as you like, and you can pin pages that you want to keep open permanently.

If you like Chrome as a browser, you’ll appreciate it as an OS. Chrome OS syncs bookmarks, settings, extensions and in-browser apps across machines. When you sign into the OS, all your settings from your Chrome browser are pulled in automatically. It runs many — but not all — of the Web apps and extensions in the Web App Store Google recently opened at http://chrome.google.com/webstore.

If you’re a Twitter user, for example, you’ll want to try the Chrome version of Tweetdeck, the popular social networking program. If not, check out Aviary, a very good photo editing app. (Even if you don’t have a Cr-48, you can use these programs and more by downloading and installing the Chrome Web browser from www.google.com/chrome.

Of course, relying on the Internet means you must have constant access to it. To ensure that, the Cr-48 can connect via Verizon’s 3G cellular data network. Cr-48 owners get a free 100 megabytes of data a month for two years, but they can purchase more access through a variety of data plans.

This is a very early version of the Chrome OS, and so it’s got plenty of rough spots. Plug a thumb drive into the Cr-48’s lone USB port, and nothing happens — there’s no real file manager for seeing what’s on the drive. Printing requires you to jump through some hoops and use a printer hooked to a Windows PC on a network. The controls in the settings are so minimalist as to be useless in some cases.

Chances are, Google will never sell the Cr-48 to consumers; it’s a prototype. But later next year, you’ll see manufacturers such as Samsung and LG sell devices that use the Chrome OS.

By definition, computing on this operating system is limiting — in its current state, the Chrome OS is not going to interest the majority of PC users. Even as a niche offering, Chrome OS PCs will need to be very inexpensive to succeed. If you’re choosing between a full-featured Windows netbook for, say, $250, or a Chrome OS device that can’t run native programs or store many files, which one would you pick?